A fibre Bragg grating based sensor for simultaneous AC current and temperature measurement

In this paper, we describe a sensor capable of measuring both AC current and temperature using a single fibre Bragg grating (FBG). The device consists of a magnetically biased magnetostrictive alloy bonded to an FBG. The magnetic field generated by the current in a specially designed coil produces internal strains in the magnetostrictive alloy which can be detected by the FBG. The temperature at the sensing point is determined through averaging of the sensor output signal. The measurement range of the sensor can be varied by altering the design of the sensor coil. A prototype sensor has been constructed capable of measuring AC currents up to 1 A while simultaneously measuring temperatures up to 100°C.